Anaerobic wastewater treatment

Anaerobic processes offer great advantages for the treatment of certain industrial effluents. This is why the number of wastewater treatment plants with anaerobic stages has grown rapidly in recent decades. They perfectly complement the range of aerobic processes.

A characteristic feature of anaerobic wastewater treatment is the high energy recovery from the organic freight via the biogas produced. The recycling rate is 80 to 90 per cent, only five per cent are converted into biomass. The remainder of the organic load, which is between five and 15 per cent depending on the application, is found in the anaerobic pre-treatment process and is normally removed in a downstream aerobic stage. Compared to pure aerobic biological treatment, this results in significantly lower energy consumption for aeration, lower costs for sludge treatment and sustainable energy generation from biogas. This can be used to generate electricity and heat in a combined heat and power unit (CHP). This electricity and heat can often be used to cover part of the energy requirements of production.

For wastewater with a COD concentration of more than 3,000 milligrams per litre and a COD load exceeding five tons per day, the use of anaerobic technology can drastically reduce operating costs. Typical areas of application for anaerobic processes are wastewater from the paper industry, the chemical industry and the food industry, for example in sugar factories, breweries, distilleries, in soft drink production and vegetable and fruit processing.

The energy balance of an anaerobic process varies from case to case and depends largely on the COD concentration and COD load. Further factors are the proportion of filterable substances (TSS), nitrogen and sulphate as well as the temperature and degradability of the waste water.

H+E will show you the differences between an anaerobic process and an aerobic process for your individual problem and offer you the anaerobic technology best suited to your needs. Our anaerobic waste water treatment plants have been used in the sugar and other food industries for years and ensure reliable treatment results even under fluctuating feed conditions.

The most important anaerobic technologies at a glance:

  • UASB (upflow anaerobic sludge blanket)
  • EGSB (expanded granular sludge bed, such as our ANAFIT®.AC)
  • Contact sludge process (also see our ANAFIT®.CS reactor)


Our references

Germany 2023

Wastewater treatment at a chemical site rich in tradition

InfraLeuna GmbH and its associated companies are the owners and operators of the infrastructure facilities at Leuna, a chemical site rich in tradition. InfraLeuna GmbH pursues the goal of shaping and developing the framework conditions for the production operations of its customers at the site. This involves the supply of necessary media such as energy and water, disposal through the central wastewater treatment plant and analytical services in its modern laboratory.

Austria 2020

High-End UPW Plant for the Semi-Conductor Industry

The task was to implement a high-end ultrapure water plant for the treatment of well water for a well-known semiconductor manufacturer in Central Europe.

Estland 2020

Award Winner: AS Estonian Cell

In 2020, AS Estonian Cell was declared the winner of the competition ”Environmentally Friendly Company of the Year in Estonia“. With H+E components Estonian Cell came a significant step closer to its goal of becoming the best producer of pulp in the world.

Malaysia 2014

Offshore High Pressure High Performance Produced Water Treatment Package

A high-pressure high-efficiency produced water treatment system of Petronas an Sapura Energy designed to meet strict overboard discharge limits while accommodating onerous space and weight constraints imposed by offshore design requirements.

Denmark 2014

Oily Water Treatment Offshore

For an oil rig, Ørsted needed a treatment plant for treating oily water from various sources. Ørsted, Denmark, is the world market leader in offshore wind energy and offers innovative energy solutions for public utilities and industry.

For an oil rig, Ørsted needed an oily water treatment plant to treat water from various sources to remove oil down to <10 mg/l and 95% of solids >100 μm, making the water suitable for discharge into the sea. This application was a particular challenge due to the small droplet diameters and emulsified oils from the various sources. H+E met the challenge by providing their coalescer design with a solids removal system upstream of the coalescer technology.

Germany 2012

New AOP application in a German paper mill

MD Papier GmbH, which belongs to the UPM Group, is one of Germany’s largest manufacturers of high-quality magazine papers. Due to a shift of production to higher-grade and higher bleached products, the percentage of persistent, non-biodegradable wastewater constituents has increased.